This invention relates to hair conditioning compositions.
Healthy, undamaged hair can be naturally difficult to comb, especially when wet. Damaged hair, such as can result from exposure to excessive heat and dryness (e.g., blow-drying, sun, and wind) and from chemical treatments (e.g., bleaching or coloring and permanents which curl or straighten the hair) can be even more difficult to comb.
Hair conditioners designed to improve the combability of the hair typically contain a cationic composition(s) as the active conditioning ingredient or ingredients that is designed to reduce static as well as generally condition; fatty alcohols, waxes, or resins to provide a thick cream vehicle for the active ingredient(s); proteins; humectants; and various perfunes and preservatives. These ingredients are typically combined either with a hydrophilic emulsifier to produce an oil-in-water emulsion or with a suspending agent or a thickener (e.g. a cellulose gum). In these formulations, the lipophilic part of the active ingredient is in the oil phase which, by the action of the emulsifier or dispersion agent, exists as small droplets within the larger amount of water (the external phase). The external aqueous phase characteristic of these distribution systems has been considered to be a necessary component of hair conditioning compositions since one of the criteria for such compositions is that they must be easily rinsed from the hair after application. Such compositions are relatively inefficient in delivering the active ingredient(s) contained in the oil phase to the hair. Dispersions and oil-in-water emulsions tend to form beads on the hair shafts so the conditioning agents are not uniformly distributed throughout the hair. Further, since the active ingredient is widely dispersed as small droplets within the bead, the bead must be physically worked, e.g., by rubbing the conditioner into the hair, so as to bring the oil phase into contact with the hair shaft. In addition to being an inefficient method of delivering the active ingredient to the hair, such working can further damage or break off already-weakened hair.
Another factor contributing to the inefficiency of typical conditioners is the significant amount of solid (i.e., non-volatile) ingredients used in addition to the key cationic ingredient. Such other ingredients include fatty alcohols, waxes, thickeners, proteins, and the like. The total content of such ingredients in a typical commercially-available conditioner range from about 2.5% to about 10%. Those ingredients tend to deposit on the hair and form a tacky surface which attracts dust and other airborne particulates, causing the hair to become dull-looking and dirty. The surface coating can also give the hair a greasy look and feel. Further, the solids can weigh the hair down (especially after collecting dust and other particulates) leaving the hair flat with no body or fullness.
In general, the invention features a hair conditioning composition consisting of a water-in-oil emulsion containing less than about 0.5%, and preferably no more than about 0.3% of the active ingredient, that active ingredient being dissolved, to a significant extent, in the external oil phase of the emulsion so that it comes into direct contact with the hair upon application. Less than about ten percent, more preferably six-eight percent, of the oil phase is needed. The composition also contains up to about three percent of an emulsifier material. The conditioning composition preferably has a viscosity of from about 1000 to about 8000 centipoises, more preferably a viscosity of from about 4000 to about 6000 centipoises.
Conditioners according to the invention have a thinner texture and a lighter feel than typical high-solids oil-in-water emulsion conditioners. When applied to the hair, the water-phase portion of conditioners according to the invention rinses away easily, leaving the hair with significantly improved combability. During drying, the volatile oil portion of the conditioner evaporates rapidly and with a slight cooling effect, in contrast to the heavy, greasy feeling which often accompanies typical conditioners.
In addition to having a lighter, cleaner feel, conditioners according to the invention are more efficient in delivering the active ingredient (i.e., the cationic hair conditioning agent) to the hair. The external oil phase delivers the conditioner smoothly along the hair shafts, producing a more uniform distribution of the condtioner on the hair. Since the active ingredient (the conditioning agent) is in the external phase, the conditioner does not have to be physically worked to bring the conditioning agent into contact with the hair. Quaternary and/or amine conditioning compounds having an HLB of less than about 12 were found to deliver conditioning benefits with the least oily or greasy feel imparted to the hair. A water-in-oil conditioning emulsion in accordance with the invention functions effectively with a small fraction of the active ingredient usually contained in oil-in-water conditioning emulsions. Little residue is left on the hair after rinsing and drying the hair since the formulations have low total solids contents. While some of the volatile oils remain after rinsing, these evaporate within a short period of time and so do not build up on the hair. The slight amount of residue minimizes the problems of attracting dust, making the hair appear dull or greasy, and weighing the hair down.
Formulations in accordance with the invention impart a greater conditioning effect to the hair than would be expected based solely on the amounts of the active ingredient(s) present, due to the efficiency of delivery. Because of the system delivery efficiency, other solid ingredients can be added; the resulting conditioner still being significantly more effective and efficient than typical oil-in-water emulsions and dispersions in delivering the active ingredient(s) to the hair.
The essential components of formulations according to the present invention, as indicated above, are (1) a volatile oil, (2) an emulsifier which when properly mixed with the remaining components yields a water-in-oil emulsion, (3) a cationic hair conditioning agent which is at least partially soluble in the volatile oil, and (4) a water phase.